Agronomical practice for the protection of crops and new composition of matter



nited States Patent AGRONOMICAL PRACTICE FOR THE PROTEC- TION OF CROPSAND NEW COMPOSITION OF MATTER Charles R. Youngson, Long Beach, and CleveA. I. Goring, Garden Grove, Califl, assignors to The Dow ChemicalCompany, Midland, Mich., a corporation of Delaware No Drawing. FiledFeb. 1, 1957, Ser. No. 637,611

Claims. (Cl. 167-39) The present invention relates to fumigantcompositions and is particularly concerned with a new fumigantcomposition and an agronomical practice for improving the ability ofsoil to support plant growth.

It is an object of the present invention to provide a new fumigantcomposition. A further object is to provide a new agronomical practicefor improving the plant growing properties of soil and the ability ofsoil to support the growth of crops. Another object is the provision ofa new method and composition for treating soil to obtain improvedcontrols of soil-dwelling invertebrate organisms such as wire worms andnematodes. A further object is the provision of a new method andcomposition for improving the emergence seedling growth and the harvestof crop plants. An additional object is the provision of a new methodand composition for treating soil which will accomplish the stimulationof the growth of crops. Other objects will become apparent firom thefollowing specification and claims.

The new fumigant composition of the present invention comprises about 1part by weight of 1,2-dibromo-3-chloropropane in admixture with fromabout 0.1 to 3 parts by weight of 1,3-dichl0ropropene. While thiscomposition advantageously may be employed in many types of fumigantoperations, it conveniently adapts itself to the treatment of soil orother growth media to improve the ability of the soil to support plantgrowth and to benefit the plants grown in the treated soil. Suchpractice protects the plants from the ravages of soil-dwellinginvertebrate organisms which atack their roots and improves the growthand harvest of crop plants. It has also been found that the treatmentaccomplishes changes in the soil which stimulate the growth and improvethe growth characteristics of crops grown therein. \It is among theadvantages of the present invention that the toxicants in the mixtureappear to be mutually activating so that a greater than additive orsynergistic result is accomplished as regards the effect on the plantgrowing properties of the soil and the control of insect and otherundesirable organisms and particularly invertebrates such as wire wormsand nematodes.

The composition comprising the mixture of toxicants is sufficientlyincreased in effectiveness so as to permit the utilization of reducedamounts of 1,3-dichloropropene and of 1,2-dibromo-3-chloropropane onsoil and the obtaining of crop yields and controls of soil-dwellingorganisms which are much superior to those obtained when either of theconstituents of the mixture is employed alone. An additional advantageis that these reduced effective dosages of the mixture of toxicantsmaterially reduce the hazards of soil residues. Thus, the practice ofthe present invention provides a very desirable economic advantage forthe agriculturist.

1,Z-dibromo-S-chloropropane and l,3dichloropropene are mobile liquidsboiling at 185 C. and 107-111 C. at atmospheric pressure, respectively.Mixtures of the compounds are soluble in many organic solvents and oflow solubility in water and are adapted to be readily and convenientlydistributed in soil. It is among the advantages of the present inventionthat mixtures of these compounds, while sufiiciently persistent toaccomplish the desired effect upon the soil and upon the soil inhabitingorganisms dissipate in a reasonable period oi? time. Still anotheradvantage is that mixtures of these compounds permeate soil for adistance of several inches from the point of application depending uponthe temperature, or ganic content, moisture content, compactness andphysical consistency of the soil or growth media.

In carrying out the improved agnonomic practice of the invention, the1,Z-dibromo-3-chloropropane and 1,3-dichlorop-ropene components of thecompositions may be mixed together and employed directly for thetreatment of soil. However, the present invention also embraces theemployment of gaseous, liquid or dust compositions containing themixture of toxicants and for any fumigant purpose where the compositionis valuable. Thus, the toxicant mixture may be dissolved together in asuitable liquid carrier to provide compositions adapted to bedistributed in soil. Such liquid compositions may also be employed tofumigate the surfaces of certain fruits, vegetables and grains wherethese products toleratethe fumigation action. Similarly, the1,2-dibromo-3-chloropropane and 1,3-dichloropropene may be dispersedtogether on or in a granular or finely divided solid carrier to providecompositions adapted to be distributed in soil or employed asconcentrates and subsequently diluted with additional inert carrier toproduce the ultimate treating compositions. In a further mode ofoperation, the 1,2-dibromo-3-chloropropane and 1,3-dichloropropene maybe blended with a suitable surface-active dispersing agent with orwithout one or more liquid carriers to provide concentrates suitable fordispersion in water to prepare soil treating compositions in the form ofaqueous dispersions or emulsions.

The compositions of the invention may be prepared in any suitablefashion. Since the 1,2-dibromo-3-chloropropane and 1,3-dichloropropenecompounds are miscible in all proportions, compositions without carriersmay be prepared by simple mixing of the components at ordinarytemperatures. In the preparation of compositions containing a liquidorganic carrier, the 1,2-dibromo-3-chloropropane and 1,3-dichloropropeneare thoroughly mixed in the liquid organic carrier at ordinarytemperatures. Suitable liquid organic carriers include liquid aliphaticand aromatic hydrocarbons such as toluene, xylenes, naphthas andhydrocarbon mixtures derived from the distillation of petroleum or coal.For some fumigation operations such carriers as carbon tetrachloride orethylene dichloride may be employed. In general, it is preferred toavoid liquid carriers having such low flash points as to constitute afire hazard or such high boiling points as to leave undesired residuesafter use of the compositions. Depending upon the concentration of themixture of toxicants, such augmented compositions are adapted to bedistributed in the soil or otherwise, or employed as concentrates andsubsequently diluted with additional carrier to produce the ultimatetreating compositions.

In a preferred embodiment of the invention, selected petroleumdistillates are employed as liquid carriers. Petroleum distillates usedin such embodiment are carefully fractionated portions boiling almostentirely under 400 F. at atmospheric pressure and having a flash pointabove about F. These fumigant compositions are characterized by havingexcellent penetrating properties and by being of low fire hazard to theshipper and user.

In the preparation of dispersible concentrate compositions, thel,2-dibromo-3-chloropropane and 1,3-dichloropropene components are mixedtogether in the proportions previously set forth together with asurface-active dispersing agent soluble in the composition with orwithout the further addition of a liquid organic carrier. Thesurface-active agents are usually employed in the amount of from 1 to 20percent by weight of the combined weight of the toxicant mixture andsurface-active agent. Suitable surface-active dispersing agents includepolyoxyalkylene derivatives of alcohols, phenols and organic acids,oil-soluble petroleum sulfonates and polyoxyethylene derivatives ofglycerol, glycols and the like.

In compositions in which the 1,2-dibrorno-3-chloropropane and1,3-dichloropropene components are dispersed on or in a granulated orfinely divided solid carrier, said components may be added directly tothe solid carrier with mechanical mixing. Alternatively, the componentsmay be combined with one or more of the aforementioned liquid organiccarriers and the resulting compositions admixed with the solid carrier.Suitable solid carriers include silica gel, woodfiour, fullers earth,chalk or gypsum and the like. 7

In formulating the compositions, it is essential to maintain theproportions of from about 1 part by Weight of1,2-dibromo-3-chloropropane to from about 0.1 to 3 parts by weight of1,3-dichloropropene and to provide an effective amount of said mixturein the finished composition in order to obtain the desired synergisticeffect. The concentration of the mixture of toxicants in organic solventcompositions employed to supply the desired dosage is generally fromabout to 85 percent by weight. With aqueous compositions, the requireddosage is generally supplied with compositions containing from 1 to 50percent, although concentrations of 0.0002 percent by weightconveniently may be employed in irrigation treatments of soil. Incompositions wherein the active mixture is dispersed on the solidcarrier, it is generally desirable to employ from about 1 to aboutpercent by weight of the above mixture of active ingredients in thefinished solid composition. With high capacity carriers, such as silicagel, the active ingredients may amount to 50 percent by weight or moreof the solid composition. In any case, it is desirable to employsufficient of the solid carrier so that the liquid composition isadsorbed or absorbed to provide a free-flowing solid mixture. Incompositions to be employed as concentrates, the toxicant mixtureoftentimes is present in a concentration of from about 5 to 95 percentby weight.

The soil may be treated with the toxicant mixture or a compositioncontaining the mixture of toxicants in any suitable fashion. With liquidcompositions, good results have been obtained by depositing the activefumigant mixture at regular intervals beneath the surface of the soil.Such deposition may be accomplished readily by automatic machinery or byhand-operated apparatus. Thus, the active composition may be sprayed orotherwise deposited in a furrow which is subsequently closed to keep theactive agents in the desired zone of the soil to be treated.Alternatively, the liquid compositions may be injected into the soil atpredetermined intervals. In any case, the active composition is usuallydeposited at a depth of from about 4 to 18 inches below the soilsurface.

In row treatments it is advantageous to place the fumigant compositionat least 12 inches below the surface of the seed bed and to seal in thefumigant by listing the soil or by other suitable means such as ringrollers or press sealers attached behind the applicator. In overallapplication with chisel-type applicators, the fumigant composition maybe applied in uniform treatments 1 to 12 inches apart at a depth of 6 to8 inches. With plowsole applications, it is desirable to employ about 8inches spacing between the furrows and to spray or otherwise introducethe fumigant composition so as to cover the bottom of the furrow. Whereinjection of the active composition at intervals is employed, goodresults are obtained when injecting at intervals of from 3 to about 12inches, although somewhat greater intervals may be employed in certaincases. In the above operations, it is desirable to apply the fumigantcomposition after the soil has been worked into seed bed condition andwhen the soil temperature is above 50 F. and the soil moisture contentis suflicient for seed germination.

In another mode of operation, the fumigant composition in emulsifiableform may be dispersed in water employed to irrigate the soil. In thismethod, the amount of water may be varied in accordance with theporosity and water-holding capacity of the soil in order to obtain thedesired depth of distribution of the toxicant mixture.

The amounts of the l,2-dibromo-3-chloropropane and 1,3-dichloropropenecomposition to be employed will vary depending upon such factors as thetype and condition of the soil, the varieties and growth stages of soilpests to be controlled and the particular crop to be planted thereafter.The essential criterion is to employ an amount for accomplishing thedesired effect upon the soil dwelling invertebrate organisms and theplant growing properties of the soil. In general, good results areobtained when the mixture of toxicants is distributed in a growth mediato a depth of from 4 to 12 inches and at a dosage of at least 1 poundper acre. In field applications, the mixture of toxicants is usuallyintroduced into the soil at a depth of about 6 inches and at a dosage offrom 1 to 50 pounds per acre. Where compositions embodying a liquid orsolid carrier are used, the amount of composition is adjusted todistribute substantially the above-described amounts of the activetoxicant mixture per acre. The required amount of the toxicant mixturein the soil conveniently may be supplied per acre treated in from about10 to 100 gallons of organic solvent carrier, in from 10 to 162,000gallons or more of the aqueous carrier or in from about 50 to 1,000pounds or more of the solid carrier.

When operating in accordance with the present invention, it is generallydesirable to allow at least about 10 days after application of theactive composition before planting the treated area to a crop. Duringsuch period, the fumigant mixture, after accomplishing its desiredetfects, is dissipated from the soil by processes such as leaching,volatilization and chemical degradation. If high dosages of the activecomposition are employed or if the temperature remains below about C. orthe soil is sealed by heavy rains or irrigation, a somewhat longerwaiting period is desirable before planting. When employing high dosagesor following periods of low temperature or high soil moisture, it issometimes desirable to work the soil by harrowing or tilling severaldays before planting in order to facilitate the dissipation of thefumigant composition from the soil.

The following examples illustrate the invention but are not to beconstrued as limiting:

EXAMPLE 1 Amount of Toxicant in Grams per Liter of Acetone Composition1,2-dibromo43- ohloropropane These compositions were employed for thetreatment of sandy loam soil heavily infested with root-knot nematodes.In such operations, the soil was placed in scalable containers andthereafter treated with the compositions by injection to give variousdosages of toxicant per acre foot of soil. The containers of treatedsoil were then sealed and set aside for one week. Containers ofuntreated soil were similarly sealed and set aside to serve as checks.

Following the latter period, the containers were unsealed and the soilallowed to aerate for one week and thereafter planted with tomato seeds.During the sub- Dosage of Toxicant in Pounds per Acre Foot of SoilPercent Composition Control of Nematodes 1,?rdibromo- 1,3-dichloro-3-chloropropropene pane In the check plots which received no treatment,the plants were found to be dwarfed and their roots covered with gallsattributable to nematode attack.

EXAMPLE 2 1,2-dib1'om0-3-chl0ropropane and 1,3-dichloropropene weredissolved in acetone to produce the following compositions:

Amount of Toxicant in Grams per Liter of Acetone Composition1,2-dibromo- 1,3-dichloro- 3-ohloropropropane pane These compositionswere employed for the treatment of sandy loam soil infested withroot-knot nematodes. In such operations, the soil was placed in sealablecontainers and thereafter treated with the compositions by injection togive various dosages of toXicant per acre foot of soil. The containersof treated soil were then sealed and set aside for one week. Containersof untreated soil were similarly sealed and set aside to serve aschecks.

Following the latter period, the containers were unsealed and the soilallowed to aerate for one Week and thereafter planted with tomato seeds.During the subsequent growing period, there was observed no adverseeffect upon the growth of the seedlings attributable to the presence ofresidual toxicant. About 7 weeks after planting, the plants were liftedfrom the soil and their roots washed and examined for gall formation dueto nematode attack. The results obtained together with the dosages atwhich the toxicants were employed are set forth in the following table:

In the check plots which received no treatment, the plants were found tobe dwarfed and their roots heavily galled as a result of nematodeattack.

6 EXAMPLE 3 Composition A Fifteen parts by weight of1,2-dibromo-3-chloropropane, 37 parts of 1,3-dichloropropene, 45 partsof Xylene and 3 parts of a dimeric alkylated aryl polyether alcohol(Triton X155) are mixed together to prepare a concentrate composition inthe form of an emulsifiable liquid.

Composition B In a further operation, 30 parts by weight of1,2-dibromo-S-chloropropane, 40 parts of 1,3-dichloropropene, 28 partsof Xylene and 2 parts of an alkyl aryl sulfonate (Nacconal NR) aremechanically mixed together to produce a water-dispersible concentratecomposition.

Composition C Also l,2-dibromo-3-chloropropane and l,3-dichloropropeneare dissolved in a low boiling petroleum hydrocarbon fraction (Stoddardsolvent) to produce a composition having a flash point greater than 100F. and containing about 20 percent by weight of each of the toxicantcompounds. The hydrocarbon solvent has a boiling range of from about 325to 390 F. and a flash point of about 116 F.

Composition D In an additional operation, 1,2-dibromo-3-chloropropaneand 1,3-dichloropropene are dissolved in Standard Thinner 250 to producea fumigant composition containing 30 percent by weight of1,2-dibromo-3-chloropropane and 10 percent by weight of1,3-dichloropropene. Standard Thinner 250 is a petroleum hydrocarbonfraction boiling at from 192 to 272 F.

The concentrate compositions as above described are adapted to bedispersed in water to produce aqueous compositions having very desirablewetting and penetrating properties. The latter aqueous compositions andthe above described solvent fumigant compositions are adapted to beemployed to treat soil and to distribute the mixture of toxicantstherein in effective concentrations.

EXAMPLE 4 1,2-dibromo-3chloropropane and 1,3-dichloropropene weredissolved in acetone to produce the following compositions:

Amount of Toxicant in These compositions were employed for the treatmentof sandy loam soil heavily infested with root knot nematodes. In suchoperations, the soil was placed in sealable containers and thereaftertreated with the compositions by injection to give various dosages oftoxicant per acre foot of soil. The containers of treated soil were thensealed and set aside for one week. Containers of untreated soil weresimilarly sealed and set aside to serve as checks.

Following the latter period, the containers were unsealed and the soilallowed to aerate for one week and thereafter planted with tomato seeds.During the subsequent growing period, there was observed no adverseeffect upon the growth of the seedlings attributable to the presence ofresidual toXicant. About 7 weeks after planting, the plants were liftedfrom the soil and their roots washed and examined for gall formation dueto nematode attack. The results obtained together with the dosages atwhich the toxicants were employed are set forth in the following table:

The roots of the tomato plants in the check plots which received notreatment were heavily covered with galls resulting from nematodeattack.

EXAMPLE Composition A as described in Example 3 is dispersed in water toproduce a composition containing about 20 pounds of the mixture oftoxicants per 200 gallons of ultimate mixture. The latter composition,while under agitation, is metered into irrigation water at the pumpoutlet at the rate of 2 gallons per 1,000 gallons of irrigation Water.The Water is in a state of turbulent flow as it comes from the pumpwhich provides for the thorough mixing of the toxicants therein. About 2acre inches of irrigation water is applied per acre to land heavilyinfested with wire worms and root-knot nematodes to accomplish a wettingof the soil to a depth of about 12 inches. Two weeks after thetreatment, the soil is planted with tomatoes. In a check operation,adjacent but similarly infested soil is also planted with tomatoes.Eight weeks after seeding, the plots are inspected and representativeplants lifted from the soil and their roots examined for evidence ofwire Worm and nematode attack. The examination indicates a commercialcontrol of both soil organisms in the treated soil with severeinfestation in the check plots.

We claim:

1. A fumigant composition consisting essentially of as active toxicingredients from about 1 part by weight of 1,2-dibromo-3-chloropropaneand from about 0.1 to 3 parts by weight of 1,3-dichloropropene.

2. A fumigant composition consisting essentially of a carrier anddispersed therein as active toxic ingredients from about 1 part byweight of 1,2-dibromo-3-chloropropane and from about 0.1 to 3 parts byweight of 1,3- dichloropropene, the active toxic ingredients of saidcomposition being mutually activating.

3. A composition consisting essentially of as active toxic ingredientsfrom about 1 part by weight of 1,2-dibromo-3-chloropropane and fromabout 0.1 to 3 parts by weight of 1,3-dichloropropene in intimateadmixture with an adjuvant selected from the group consisting of (A)finely divided inert solids, (B) emulsifying and dispersing agents, and(C) petroleum distillates, the amount of such adjuvants employed in thecompositions being from to 99 percent by weight for (A), from 1 to 20percent by weight for (B), and from 15 to percent by weight for (C).

4. A composition claimed in claim 3 wherein the active toxic ingredientsare admixed with a finely divided inert solid.

5. A composition claimed in claim 3 wherein the active toxic ingredientsare admixed with a petroleum distillate.

6. A composition claimed in claim 3 wherein the active toxic ingredientsare admixed with a surfaee-active dispersing agent.

7. A fumigant composition consisting essentially of an aqueousdispersion of the composition claimed in claim 6, the mixture of activetoxic ingredients being present in the amount of at least 0.0002 percentby weight.

8. In the practice of agricultural economy, the method which comprisesimpregnating soil with a parasiticidal dosage of a compositionconsisting essentially of from about 1 part by weight of1,2-dibromo-3-chloropropane and from about 0.1 to 3 parts by weight of1,3-dichloropropene.

9. In the practice of agricultural economy, the method which comprisesimpregnating soil with a parasiticidal dosage of a compositionconsisting essentially of as active toxic ingredients from about 1 partby weight of 1,2-dibromo-3-chloropropane and from about 0.1 to 3 partsby weight of 1,3-dichloropropene in intimate admixture with a petroleumdistillate.

10. A fumigant composition consisting essentially of 1,3-dichloropropeneand 1,2-dibromo-3-chloropropane, the weight of the1,2-dibromo-3-chloropropane being from about 25 percent to 90 percent ofthe sum of the weights of the 1,3-dichloropropene and the1,2-dibromo-3-chloropropene.

Action of Insecticides and a Short Cut in Analysis, US. Dept. Agr. Pub.ET-223, June 1945 (7 pp.).

10. A FUMIGANT COMPOSITION CONSISTING ESSENTIALLY OF 1,3-DICHLOROPROPENEAND 1,2-DIBROMO-3-CHLOROPROPANE, THE WEIGHT OF THE1,2-DIBROMO-3-CHLOROPROPANE BEING FROM ABOUT 25 PERCENT TO 90 PERCENT OFTHE SUM OF THE WEIGHTS OF THE 1,3-DICHLOROPROPENE AND THE1,2-DIBROMO-3-CHLOROPROPENE.